"I'm never going to be the same. I'm not going to be able to live like this," Murray said, urging the judge to impose the maximum sentence.

Sira followed through on the request for the maximum, sentencing Stover to 25 years to life for second-degree murder and an additional 1 1/3 to 4 years for tampering with evidence in the case.

After killing Knowles, Stover deleted incriminating emails and got rid of the murder weapon. That illegally owned handgun is "still out on the street now," prosecutors said Tuesday.

In mid-June, a Schenectady County jury found Stover guilty of firing a bullet into Knowles' head on Sept. 15 inside 524 Schenectady St.

"This wasn't a case of a momentary loss of control or a lapse in judgement," Assistant District Attorney Christina Tremante-Pelham said Tuesday. "Raekwon Stover made a series of choices and deliberate acts."

Stover learned Knowles had not gone to a prearranged meeting with a john that afternoon, argued with her about why and left to get bullets before he killed her that evening, Tremante-Pelham said.

Stover, who was romantically involved with the victim, shot Knowles as she yelled for her mother. At trial, a neighbor testified about hearing the shot.

On Tuesday, Murray looked directly at Stover and said that, while she was startled awake by gunfire, she had not heard her child's pleas for help.

"I could have been there," Murray sobbed, as Stover silently brushed away his own tears.

Prosecutors said Stover shot Knowles because, among other reasons, she decided to stop being a sex worker for him.

"She was a 17-year-old girl who found herself in her final months under the control of a man who used her," Tremante-Pelham said. "Her final moments were spent terrorized by him."

The jury convicted Stover of all charges, which included second-degree murder, two counts of criminal possession of a weapon and tampering with evidence.

Knowles left behind a 3-year-old son, Jahsiy, who family said has struggled to understand the finality of his mother's death.

"He's such a smart 3-year-old: full of life and energy, so pure, so innocent," Knowles' uncle Marcus Goodman told the judge. "We, as a family, have to sit him down and explain this all over again: how he was in the house when his mother's murder took place. Can you imagine that conversation?"

Knowles, who family members described as selfless and kind, was the second oldest of five children. Her mother told the judge that the three youngest kids missed a significant amount of school in their grief and were forced to attend summer school.

The family also lost their apartment and most of their possessions, Murray said, because she was emotionally unable to return to the place where her daughter died. Murray said she's been diagnosed with post-traumatic stress disorder and is haunted by vivid recollections of the night her daughter was slain.

In her final hours, the teen had posted on Facebook over a dozen times about relationships, spurned exes and conflict with other women, including a re-posted photo that said, "Don't waste your time on revenge. Those who hurt you will face their own karma."